A5016709060- Climate variability and models
- Meteorological Phenomena and Simulations
- Tropical and Extratropical Cyclones Research
- Oceanographic and Atmospheric Processes
- Atmospheric and Environmental Gas Dynamics
- Arctic and Antarctic ice dynamics
- Flood Risk Assessment and Management
- Hydrology and Drought Analysis
- Atmospheric chemistry and aerosols
- Geophysics and Gravity Measurements
- Atmospheric aerosols and clouds
- Atmospheric Ozone and Climate
- demographic modeling and climate adaptation
- Arctic and Russian Policy Studies
- Ocean Waves and Remote Sensing
- Cryospheric studies and observations
- Ocean Acidification Effects and Responses
- Methane Hydrates and Related Phenomena
- Wind and Air Flow Studies
- Precipitation Measurement and Analysis
- Climate change and permafrost
- Integrated Energy Systems Optimization
- Energy Load and Power Forecasting
- Climate change impacts on agriculture
- Marine and coastal ecosystems
University of Reading
2016-2025
National Centre for Atmospheric Science
2016-2025
National Institute of Meteorology
2016-2023
Met Office
2016
University of Tsukuba
2016
European Centre for Medium-Range Weather Forecasts
2016
University of Oxford
2016
Lawrence Berkeley National Laboratory
2016
Abstract The response of North Atlantic and European extratropical cyclones to climate change is investigated in the models participating phase 5 Coupled Model Intercomparison Project (CMIP5). In contrast previous multimodel studies, a feature-tracking algorithm here applied separately quantify responses number, wind intensity, precipitation intensity cyclones. Moreover, statistical framework employed formally assess uncertainties projections. Under midrange representative concentration...
Extratropical cyclones are often associated with heavy precipitation events and can have major socio‐economic impacts. This study investigates how much of the total in Northern Hemisphere is extratropical cyclones. An objective feature tracking algorithm used to locate these quantified establish their contribution precipitation. Climatologies produced from Global Precipitation Climatology Project (GPCP) daily dataset ERA‐Interim reanalysis. The magnitude spatial distribution cyclone...
The ability of the climate models participating in phase 5 Coupled Model Intercomparison Project (CMIP5) to simulate North Atlantic extratropical cyclones winter [December–February (DJF)] and summer [June–August (JJA)] is investigated detail. Cyclones are identified as maxima T42 vorticity at 850 hPa their propagation tracked using an objective feature-tracking algorithm. By comparing historical CMIP5 simulations (1976–2005) ECMWF Interim Re-Analysis (ERA-Interim; 1979–2008), authors find...
The representation of the Northern Hemisphere (NH) storm tracks and jet streams their response to climate change have been evaluated in model simulations from Phases 3, 5, 6 Coupled Model Intercomparison Project (CMIP3, CMIP5, CMIP6, respectively). spatial patterns multimodel biases CMIP3, CMIP6 are similar; however, magnitudes models substantially lower. For instance, mean RMSE North Atlantic track for (as measured by time-filtered sea-level pressure variance) is over 50% smaller than that...
Western disturbances (WDs) are upper‐level synoptic‐scale systems embedded in the subtropical westerly jet stream (STWJ), often associated with extreme rainfall events north India and Pakistan during boreal winter. Here, a tracking algorithm is applied to upper‐tropospheric vorticity field for 37 years of ERA‐Interim reanalysis data, giving catalogue over 3000 events. These analysed composite framework: vertical structure explored across large number dynamic thermodynamic fields, revealing...
Abstract This article describes the development and evaluation of U.K.’s new High-Resolution Global Environmental Model (HiGEM), which is based on latest climate configuration Met Office Unified Model, known as Hadley Centre version 1 (HadGEM1). In HiGEM, horizontal resolution has been increased to 0.83° latitude × 1.25° longitude for atmosphere, 1/3° globally ocean. Multidecadal integrations lower-resolution HadGEM, are used explore impact fidelity simulations. Generally, SST errors reduced...
Abstract Composites of wind speeds, equivalent potential temperature, mean sea level pressure, vertical velocity, and relative humidity have been produced for the 100 most intense extratropical cyclones in Northern Hemisphere winter 40-yr ECMWF Re-Analysis (ERA-40) high resolution global environment model (HiGEM). Features conceptual models cyclone structure—the warm conveyor belt, cold dry intrusion—have identified composites from ERA-40 compared to HiGEM. Such features can be composite...
Abstract. The XWS (eXtreme WindStorms) catalogue consists of storm tracks and model-generated maximum 3 s wind-gust footprints for 50 the most extreme winter windstorms to hit Europe in period 1979–2012. is intended be a valuable resource both academia industries such as (re)insurance, example allowing users characterise European storms, validate climate catastrophe models. Several severity indices were investigated find which could best represent list known high-loss (severe) storms....
The Mediterranean region has been identified as a climate change "hot-spot" due to projected reduction in precipitation and fresh water availability which potentially large socio-economic impacts. To increase confidence these projections, it is important physically understand how this occurs. This study quantifies the impact on winter changes extratropical cyclones 17 CMIP5 models. In each model, are objectively tracked simple approach applied identify associated cyclone. allows us decompose...
Abstract Changes to the Northern Hemisphere winter (December–February) extratropical storm tracks and cyclones in a warming climate are investigated. Two idealized change experiments with High Resolution Global Environmental Model version 1.1 (HiGEM1.1), doubled CO2 quadrupled experiment, compared against present-day control run. An objective feature tracking method is used focus given regional changes. The climatology of from run shown be good agreement 40-yr European Centre for...
Analysis of observations indicates that there was a rapid increase in summer (June–August) mean surface air temperature (SAT) since the mid-1990s over Western Europe. Accompanying this warming are significant increases daily maximum temperature, minimum annual hottest day and warmest night an frequency days tropical nights, while change diurnal range (DTR) is small. This study focuses on understanding causes associated extreme changes. A set experiments using atmospheric component...
Abstract Recent studies of individual seasonal forecast systems have shown that the wintertime North Atlantic Oscillation (NAO) can be skillfully forecast. However, it has also been suggested these skillful forecasts tend to underconfident, meaning there is too high a proportion unpredictable noise in forecasts. We assess skill and overconfidence/underconfidence contributing EUROpean Seasonal Interannual Prediction (EUROSIP) multimodel ensemble system. Five seven studied significant for...
Large quantities of weather-dependent renewable energy generation are expected in power systems under climate change mitigation policies, yet little attention has been given to the impact long term variability. By combining state-of-the-art multi-decadal meteorological records with a parsimonious representation system, this study characterises year-to-year variability on multiple aspects system Great Britain (including coal, gas and nuclear generation), demonstrating why approaches...
The aim of this study is to investigate if the representation Northern Hemisphere blocking sensitive resolution in current-generation atmospheric global circulation models (AGCMs). An evaluation conducted how well represented four AGCMs whose horizontal increased from a grid spacing more than 100 km about 25 km. It shown that Euro-Atlantic simulated overall credibly at higher (i.e., better agreement with 50-yr reference climatology created reanalyses ERA-40 and ERA-Interim). improvement seen...
Abstract. The response of East Asian Summer Monsoon (EASM) precipitation to long term changes in regional anthropogenic aerosols (sulphate and black carbon) is explored an atmospheric general circulation model, the component UK High-Resolution Global Environment Model v1.2 (HiGAM). Separately, sulphur dioxide (SO2) carbon (BC) emissions 1950 2000 over Asia are used drive model simulations, while kept constant at year level outside this region. EASM examined by comparing simulations driven...
The winter season of 2013/2014 was the stormiest on record for British Isles. In this article we show that there an unprecedented amount cyclone clustering during season, corresponding to average one intense affecting country every 2.5 days. An intensely clustered period from 6 13 February 2014 associated with specific family is analysed in detail. This shown be a strong and straight upper level jet flanked by Rossby wave breaking both its northern southern sides duration event. mechanism...
Abstract The Eurasian subtropical westerly jet (ESWJ) is a major feature of the summertime atmospheric circulation in Northern Hemisphere. Here, we demonstrate robust weakening trend summer ESWJ over last four decades, linked to significant impacts on extreme weather. Analysis climate model simulations from Coupled Model Intercomparison Project Phase 6 (CMIP6) suggests that anthropogenic aerosols were likely primary driver ESWJ. Warming mid-high latitudes due aerosol reductions Europe, and...
Abstract Future climate change projections are often derived from ensembles of simulations multiple global circulation models using heuristic weighting schemes. This study provides a more rigorous justification for this by introducing nested family three simple analysis variance frameworks. Statistical frameworks essential in order to quantify the uncertainty associated with estimate mean response. The most general framework yields “one model, one vote” scheme used projection. However,...
Abstract Polar lows are maritime mesocyclones associated with intense surface wind speeds and oceanic heat fluxes at high latitudes. The ability of the Interim ECMWF Re-Analysis (ERA-Interim, hereafter ERAI) to represent polar in North Atlantic is assessed by comparing ERAI operational analysis for period 2008–11. First, representation a set satellite-observed over Norwegian Barents Seas analyzed. Then, possibility directly identifying tracking explored using algorithm based on 850-hPa...
Abstract. The impact of biomass burning aerosol (BBA) on the regional climate in South America is assessed using 30-year simulations with a global atmosphere-only configuration Met Office Unified Model. We compare two high and low emissions based realistic interannual variability. scheme model has hygroscopic growth optical properties for BBA informed by recent observations, including those from American Biomass Burning Analysis (SAMBBA) intensive aircraft observations made during September...
While much of India is used to heavy precipitation and frequent low pressure systems during the summer monsoon, toward northwest into Pakistan, such events are uncommon. Here, as a third annual rainfall delivered sporadically winter monsoon by western disturbances. Such sparse but in this region typically mountainous valleys north desert south can be catastrophic, case Pakistan floods July 2010. In study, extreme (EPEs) box approximately covering (25°–38°N, 65°–78°E) identified using...
Abstract Winter 2013/14 was the stormiest on record for UK and characterized by recurrent clustering of extratropical cyclones. This associated with a strong, straight persistent North Atlantic jet also Rossby wave breaking (RWB) both flanks, pinning in place. The occurrence RWB cyclone is further studied 36 years ERA‐Interim Reanalysis. Clustering at 55°N an extended anomalously strong eddy‐driven flanked sides RWB. However, 65(45)°N has dominance to south (north) jet, deflecting northward...